110,591 reputation
6102207
bio website von-eitzen.de/math/tntrep.xml
location Bonn, Germany
age 48
visits member for 2 years, 1 month
seen 6 hours ago

I did study math and had a knack for it, but I am sooo out of that business now ...


Oct
19
comment distribution of chocolate problem?
Of course if you were wore generous to these three children, you could give $60$ to the first, $50+10$ to the second and $30+35$ to the third. The infairness then would be $10$ only and you'd still have $70$ pieces of chocolate for yourself :)
Oct
19
answered distribution of chocolate problem?
Oct
19
answered What is the Identity of the Reals mod $1$?
Oct
19
awarded  prime-numbers
Oct
18
comment Trigonometric problem in triangles.
I think $x=\sqrt{m^2+n^2}\cdot \sin(a+b)$ is easier to see
Oct
18
comment In high school statistics, why does it seem like equations come out of the sky
There's quite a difference in required math skill level between (a) applying the $\chi^2$ method to a given data set and (b) deriving the theory behind $\chi^2$ tests including insights why we require that each observation should be expected to occur a least about 5 times in order to make the test valid and where that degrees-of-freedom stuff comes from.
Oct
18
answered Chains and antichains in a family of sets
Oct
18
comment Why do the conditions $x_1+x_2=b$ and $x_1\cdot x_2=ac$ hold for any quadractic equation?
You should rather have $x_1+x_2=-\frac ba$ and $x_1x_2=\frac ca$.
Oct
18
comment finding invariant subgroups under all automorphisms
A finite such group must be the product of its Sylow groups. Now try to classify all $p$-groups having your property.
Oct
18
comment finding invariant subgroups under all automorphisms
Simple groups dont't in general. For exsmple $A_5$ contains a cyclic $5$-group that is not characteristic.
Oct
18
answered Construction of an injective homomorphism from $S_n$ to $GL(n,\mathbb R)$
Oct
18
answered Dimension of a subspace of finite-dimensional product space $V$ equals $\dim V - 1$
Oct
18
comment How can I find the value of $\ln( |x|)$ without using the calculator?
The task was to avoid a pocket calculator
Oct
18
reviewed Leave Closed Why least square problem always has solution for arbitrary b?
Oct
18
answered Show that the set is/isn't well ordered
Oct
18
answered Prove if $a+b=c+d$ and $e+f=g+h$, then $a+e+b+f=c+g+d+h$.
Oct
17
answered Solving an equation with floor function
Oct
17
answered The sequence of prime gaps is never strictly monotonic
Oct
17
answered $|3^a-2^b|\neq p$, from a contest
Oct
17
comment $|3^a-2^b|\neq p$, from a contest
@Oleg567 Now remains to be seen elementary/at contest level that $41$ cannot be written as $|3^a-2^b|$ ...